No, the Buried Sea has yet to be introduced to EQ2. That EQ1 expansion is as of yet not-canon. I would imagine that if they want to introduce some secret Combine Empire city, they should start with Katta Castellum on Luclin first.
Found them online, lol. Imagine that zone with EQ2 graphics engine = POWAH. Check out my sig, we have been discussing underwater and water related zones for some time now. Would love to see something like this in EQ2